New Zealand Co-Led Team Drills Record-Breaking Sediment Core Revealing West Antarctic Ice Sheet Retreat

The Record-Breaking Sediment Core Retrieval ❄️

In a monumental feat of polar science, a New Zealand co-led international team has successfully drilled and retrieved the longest sediment core ever extracted from beneath an Antarctic ice sheet. This 228-meter-long sample, pulled from under 523 meters of ice at Crary Ice Rise on the Ross Ice Shelf, offers unprecedented direct evidence of past retreats of the West Antarctic Ice Sheet (WAIS). The achievement, part of the SWAIS2C project, marks a breakthrough in understanding how this vulnerable ice mass has responded to warmer climates in Earth's history.

The expedition culminated after nearly a decade of planning and three field seasons, with the core recovered during the 2025/26 Antarctic summer. Scientists worked around the clock in a remote tent camp over 700 kilometers from the nearest base, battling freezing fog and technical hurdles to secure this geological treasure. Preliminary examinations reveal layers spanning approximately 23 million years, capturing episodes when open ocean conditions prevailed where thick ice now dominates.

Unpacking the West Antarctic Ice Sheet

The West Antarctic Ice Sheet, often abbreviated as WAIS, is a marine-based ice mass covering about 1.9 million square kilometers in West Antarctica. Unlike the more stable East Antarctic Ice Sheet, which rests on land above sea level, the WAIS floats in places and is grounded below sea level in many areas, making it particularly susceptible to warming ocean waters. If the WAIS were to collapse entirely, it could raise global sea levels by 4 to 5 meters, threatening coastal communities worldwide.

Satellite observations since the 1990s show the WAIS losing mass at an accelerating rate, contributing significantly to current sea level rise. However, uncertainties persist about tipping points and response times to global warming. Sediment cores like this one provide irreplaceable archives, recording environmental changes through grain size, fossils, and chemical signatures as the ice advanced and retreated over millennia.

The SWAIS2C Project: A Decade of Dedication

SWAIS2C, standing for Sensitivity of the West Antarctic Ice Sheet to 2°C, is an international collaboration involving over 120 scientists from 50 institutions across 10 countries. New Zealand plays a pivotal leadership role, with Earth Sciences New Zealand (Te Pū Ao) serving as project manager and Te Herenga Waka – Victoria University of Wellington handling drilling services. Funding comes from diverse sources, including Antarctica New Zealand, the US National Science Foundation, Germany's ICDP, and New Zealand's Antarctic Science Platform.

Co-chief scientists include Dr. Huw Horgan from Victoria University of Wellington (also affiliated with ETH Zurich), Dr. Molly Patterson from Binghamton University, and Prof. Tina van de Flierdt from Imperial College London. Earlier phases drew on expertise from GNS Science's Dr. Richard Levy. The project builds on predecessors like ANDRILL, targeting sites where ice meets bedrock to capture continuous records absent from peripheral marine sediments.

• Objectives: Quantify WAIS behavior during past warm intervals, such as the Pliocene epoch (5.3 to 2.6 million years ago), when temperatures exceeded pre-industrial levels by more than 2°C.
• Drilling Sites: Kamb Ice Stream (KIS3) in prior seasons; Crary Ice Rise (CIR) for the record core, chosen for its stable ice rise pinning the Ross Ice Shelf.
• Technology: Custom hot-water drill melts access holes; hydraulic coring system with 1,300 meters of riser pipe prevents refreezing.

Overcoming Extreme Challenges in Antarctic Drilling

Drilling beneath hundreds of meters of ice demands ingenuity. The team traversed 1,100 kilometers across the Ross Ice Shelf with specialized vehicles, establishing a self-sufficient camp. Hot water, recirculated continuously, melted a borehole while the riser pipe maintained access. Cores emerged in 3-meter sections, immediately processed: split, described, X-rayed, and sampled to preserve volatile data.

Previous attempts at KIS3 failed due to equipment issues and a 55-meter ocean cavity complicating operations. At CIR, ice directly overlies bedrock, ideal for continuous coring but riskier. The 29-person team—scientists, engineers, drillers, and polar guides—operated 24/7 for 10 weeks. Dr. Horgan noted the stress: "It was a great feeling when that first core came up, but then you start worrying about the next..." Success validated years of resilience.

Revelations from the Core: Evidence of Past Retreats

Preliminary field analysis shows dramatic shifts. Gravel-rich layers indicate grounded ice sheet override, depositing debris. Finer muds with shell fragments and light-dependent diatoms signal open water, implying Ross Ice Shelf absence and WAIS retreat. These microfossils, dated via biostratigraphy, pinpoint open-ocean phases during warmer Pliocene-like conditions.

Dr. James Marschalek from Imperial described: "layers rich in gravel and rocks... At other times, the ice sheet was much smaller... muds and shells deposited." This first in-situ evidence from WAIS interior refines models, confirming vulnerability to ocean-driven melting. Full lab analysis will use isotopes, pollen, and radionuclides for precise chronologies and paleotemperatures.

New Zealand's Pivotal Role in Global Polar Research

New Zealand's Antarctic legacy shines through SWAIS2C. Victoria University of Wellington's glaciologists and engineers led drilling innovations, while Earth Sciences New Zealand coordinates science integration. Antarctica New Zealand provided unmatched traverse logistics, enabling deep-field access.

This builds on NZ's Scott Base operations since 1957 and leadership in ANDRILL. Universities like Otago and Auckland contribute to ice core labs and modeling. For aspiring researchers, NZ offers robust programs in earth sciences, fostering careers in paleoclimatology. Explore research jobs in higher education or New Zealand academic opportunities to join such endeavors.

Implications for Sea Level Rise and Climate Adaptation

WAIS retreat could accelerate under 2°C warming, with basal melting from warm circumpolar deep water. The core's data will calibrate IPCC projections, narrowing uncertainties in 2100 sea level rise (currently 0.3-1m, higher under extremes). Coastal NZ faces inundation risks; global impacts affect 680 million near shores.

Dr. Patterson emphasized: "quantify the environmental factors that drove the ice sheet retreat, such as... ocean temperatures." Insights inform defenses like mangrove restoration or managed retreat. For higher ed, this underscores interdisciplinary needs in climate science.

Future Analysis and Expeditions

The core now journeys to Scott Base, then New Zealand labs, with subsamples to global partners. Techniques include CT-scanning, geochemical proxies (e.g., Mg/Ca for ocean temps), and dinoflagellate cysts for sea ice extent. Expected publications will detail Pliocene retreats, informing CMIP7 models.

Plans include additional coring to build a network, testing drilling scalability. Prof. van de Flierdt hailed it as "the most comprehensive picture yet of our possible future."

Careers in Antarctic Ice Sheet Research

This breakthrough highlights demand for experts in glaciology, sedimentology, and geophysics. NZ universities train via MSc/PhD programs at Victoria, Otago, and Canterbury. Skills: MATLAB modeling, core logging, stable isotopes. Early-career roles abound in field logistics to data analysis.

• Entry: Research assistantships in ice dynamics.
• Mid: Postdocs on paleoclimate proxies.
• Senior: Project leads like SWAIS2C.

Check research assistant jobs, postdoc positions, or academic CV tips on AcademicJobs.com.

NZ Higher Education's Global Impact

SWAIS2C exemplifies NZ higher ed's excellence, positioning universities as Antarctic hubs. Collaborations boost funding, publications, and rankings. For students, internships via Antarctic Science Platform offer hands-on experience.

As climate urgency grows, NZ researchers drive solutions. Interested in faculty roles? Visit professor jobs or higher ed jobs.

Photo by Adrien Olichon on Unsplash

Conclusion: Preparing for a Warming World

The SWAIS2C sediment core illuminates WAIS history, urging action on emissions. NZ's leadership inspires global efforts. Stay informed via Rate My Professor, explore career advice, or find university jobs. Together, science paves the way for resilience.